TheAlgorithms-C/searching/jump_search.c

#include <math.h>
#include <stdio.h>
#define min(X, Y) ((X) < (Y) ? (X) : (Y))
int jump_search(int *arr, int x);
int n;

int main()
{
    int arr[] = {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610};
    n = sizeof(arr) / sizeof(int);
    int x = 55;
    int index = jump_search(arr, x);
    printf("\nNumber %d is at index %d\n", x, index);
}

int jump_search(int *arr, int x)
{
    int step = floor(sqrt(n));
    int prev = 0;
    while (*(arr + (min(step, n) - 1)) < x)
    {
        prev = step;
        step += floor(sqrt(n));
        if (prev >= n)
            return -1;
    }

    while (*(arr + prev) < x)
    {
        prev = prev + 1;
        if (prev == fmin(step, n))
            return -1;
    }
    if (*(arr + prev) == x)
        return prev;
    return -1;
}